Chip mounting substrate, first level assembly, and second level assembly

ABSTRACT

A chip mounting substrate comprising: a mounting base defined by a first surface and a second surface opposite to the first surface; a plurality of first lands disposed on the first surface, being classified into first and second groups of the first lands; and a plurality of second lands disposed on the second surface so as to face to the first lands, being classified into first and second groups of the second lands.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. P2002-062893, filed on Mar. 8, 2002; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device packaging technology, more specifically to a chip mounting substrate, a first level assembly using the chip mounting substrate, and a second level assembly using the first level assembly.

2. Description of the Related Art

The increase in density and the progress in large-scale integration have continued in semiconductor integrated circuits. Especially in DRAM, thin and small package such as ball grid array (BGA) package has been widely used. In a conventional BGA package, a plurality of connection electrodes are disposed in a lower surface of a rectangular-shaped mounting base, the substrate is defined by the lower surface and an upper surface opposite to the lower surface. The connection electrodes include: a power supply terminal to which a power supply potential is supplied; an ground terminal to which an ground potential is supplied; a selection signal input terminal to which a selection signal of a semiconductor chip is fed; an input and output terminal to which an input is fed or from which output signal is provided; an address terminal to which an address signal is fed; and the like. A chip mounting area is assigned on the upper surface of the mounting base. A semiconductor chip is fixed to the chip mounting area by using an adhesive or the like. Tape-shaped thin film is used as the mounting base.

Recently, high-density packaging is required in semiconductor packaging technology. The packaging area can be reduced by a configuration such that if conventional thin-type semiconductor packages are stacked. However, connection electrodes for superimposing the plurality of semiconductor packages are not provided in the thin-type semiconductor packages. Especially, in the case where plural packages using a BGA tape are stacked, it is not possible to superimpose the packages since the lands for connecting a lower level package with an upper level package are not provided. Therefore, it has been difficult to realize high-density packaging in thin-type semiconductor packages such as a BGA package.

SUMMARY OF THE INVENTION

A chip mounting substrate comprising: a mounting base defined by a first surface and a second surface opposite to the first surface; a plurality of first lands disposed on the first surface, being classified into first and second groups of the first lands; and a plurality of second lands disposed on the second surface so as to face to the first lands, being classified into first and second groups of the second lands.

A first level assembly comprising: a mounting base defined by a first surface and a second surface opposite to the first surface; a plurality of first lands disposed on the first surface, being classified into first and second groups of the first lands; a plurality of second lands disposed on the second surface so as to face to the first lands, being classified into first and second groups of the second lands; a plurality of straight connection paths embedded in the mounting base so as to connect the first group of the first lands with the first group of the second lands just above the first group of the first lands; and a semiconductor chip mounted on a chip mounting area assigned adjacent to the second lands on the second surface.

A second level assembly comprising: a packaging board defined by a first surface assigning a substrate mounting area; a plurality of connection terminals disposed on the substrate mounting area; a plurality of signal terminals disposed around the substrate mounting area on the first surface of the packaging board; a plurality of signal wiring connected to the connection terminals and the signal terminals; a plurality of packaging balls disposed on the connection terminals, respectively; a mounting base disposed above the substrate mounting area, the mounting base being defined by a first surface and a second surface opposite to the first surface having a plurality of first lands disposed on the first surface, the first lands being classified into first and second groups of the first lands, a plurality of second lands disposed so as to face to the plurality of first lands on the second surface, the second lands being classified into first and second groups of the second lands, and a plurality of straight connection paths embedded in the mounting base so as to connect the first group of the first lands with the first group of the second lands just above the first group of the first lands; and a semiconductor chip mounted on a chip mounting area assigned adjacent to the second lands on the second surface.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an example of a first level assembly according to a first embodiment of the present invention.

FIG. 2 is an example of a sectional view seen from the I-I line in FIG. 1.

FIG. 3 is an example of a sectional view seen from the II-II line in FIG. 1

FIG. 4 is an example of a bottom view of the first level assembly shown in FIG. 1.

FIG. 5 is a view showing an example of a connection configuration of chip connection wiring from the first lands to pads of the first level assembly according to the first embodiment of the present invention.

FIG. 6 is a perspective view showing an example of a first level assembly according to a first modification of the first embodiment.

FIG. 7 is a perspective view showing an example of a first level assembly according to a second modification of the first embodiment.

FIG. 8 is a perspective view showing an example of a first level assembly according to a third modification of the first embodiment.

FIG. 9 is a perspective view showing an example of a first level assembly having a two-level constitution according to a second embodiment of the present invention.

FIG. 10 is an example of a sectional view seen from the line III-III in FIG. 9

FIG. 11 is a perspective view showing an example of a first level assembly having a three-level stacked structure according to a modification of the second embodiment of the present invention.

FIG. 12 is an example of a sectional view seen from the line IV-IV in FIG. 11.

FIG. 13 is a perspective view showing an example of a mounting substrate of a second level assembly according to a third embodiment of the present invention.

FIG. 14 is a perspective view showing an example of a packaging state of the second level assembly in FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of the present invention will be described with reference to the accompanying drawings. It is to be noted that the same or similar reference numerals are applied to the same or similar parts and elements throughout the drawings, and the description of the same or similar parts and elements will be omitted or simplified. Generally, and as it is conventional in the representation of semiconductor devices, it will be appreciated that the various drawings are not drawn to scale from one figure to another nor inside a given figure, and in particular that the layer thicknesses are arbitrarily drawn for facilitating the reading of the drawings. In the following descriptions, numerous details are set forth such as specific signal values, etc. to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details.

The assembly of levels of electronic devices is classified into several packaging levels in a hierarchy. A first level assembly in the hierarchy indicates an assembly in which a semiconductor chip is mounted on a mounting base and the like. For example, FIGS. 1 to 12 show the first level assemblies 100, 101, 102, 103, 200, and 300. A second level assembly in the hierarchy indicates an assembly in which the first level assembly is mounted on a board. The second level assembly in the hierarchy includes a second level assembly 400 as shown in FIG. 14. A third level assembly indicates an assembly in which the second level assembly is mounted on a motherboard or the like.

(First Embodiment)

The first level assembly 100 according to a first embodiment of the present invention encompasses, as shown in FIGS. 1 and 2: a mounting base 1A which is defined by a first surface and a second surface opposite to the first surface; first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . which are disposed on the first surface; second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . which are disposed, opposite to the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . on the second surface; and through-holes 6 a, 6 b, . . . , 6 f, . . . which are embedded in the mounting base 1A, so that some of the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . are connected to some of the second lands 4 a, 4 b, 4 e, . . . , 4 f, . . . just above the some of the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . . Joint balls 5 a, 5 b, 5 c, . . . , 5 f, . . . are disposed on the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . , respectively. The second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . which are opposite to the first lands 7 a, 7 b, 7 c, . . . , 7 f . . . are aligned along two lines, two sets of two lines are disposed on opposing sides of a square that defines the periphery of the mounting base 1A. In the center of the second surface of the mounting base 1A, a chip mounting area 2A is assigned adjacent to the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . . A semiconductor chip is fixed to the chip mounting area 2A with an adhesive and the like.

As shown in FIG. 2, as to the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . , for example, a first power supply terminal 7 a, a first ground terminal 7 b, a first inter level connection terminal 7 c, a first intra substrate connection terminal 7 d, a first input and output terminal 7 e, and a first address terminal 7 f can be assigned on the first surface of the mounting base 1A. A power supply joint ball 5 a, a ground joint ball 5 b, a inter level joint ball 5 c, an intra substrate joint ball 5 d, an input and output joint ball 5 e, and an address joint ball 5 f are respectively connected to the first power supply terminal 7 a, the first ground terminal 7 b, the first inter level connection terminal 7 c, the first intra substrate connection terminal 7 d, the first input and output terminal 7 e, and the first address terminal 7 f. Furthermore, other than the power supply joint ball 5 a, the ground joint ball 5 b, the inter level joint ball 5 c, the intra substrate joint ball 5 d, the input and output joint ball 5 e, and the address joint ball 5 f, a write terminal joint ball and the like, which are not shown in the drawing are included as the joint balls. The first power supply terminal 7 a, the first ground terminal 7 b, the first input and output terminal 7 e, and the first address terminal 7 f (the first group of the first lands) are electrically connected to the second lands 4 a, 4 b, 4 e and 4 f (the first group of the second lands) which are just above 7 a, 7 b, 7 e and 7 f by the through-holes 6 a, 6 b, 6 e, and 6 f (straight connection paths) embedded in the mounting base 1A.

Through-holes 6 a, 6 b, 6 e and 6 f, conductive materials are fully embedded, or partly filled so that inner wall films are formed on the inner surface of the through-holes 6 a, 6 b, 6 e and 6 f, thus connection between the first surface and the second surface is implemented. The first inter level connection terminal 7 c is electrically connected to a semiconductor chip 3A by wiring provided in the mounting base 1A, which is not shown in the drawing. The first intra substrate connection terminal 7 d (the second group of the first lands) is connected to a second inter level connection terminal 4 c (the second group of the second lands) on the second surface detoured intra substrate connection wiring in a bent through-hole 9 (bent connection path), which has a stair-step shape and is embedded in the mounting base 1A. Note that, a second inter level connection terminal 4 c is not connected to the semiconductor chip 3A mounted on the mounting base 1A, nor to the other first lands 7 a, 7 b, . . . , 7 f, . . . .

An second intra substrate connection terminal 4 d is provided on the second surface which is opposite to the first intra substrate connection terminal 7 d for intra substrate connection in the mounting base 1A interposed therebetween. The second intra substrate connection terminal 4 d is not connected to any through-holes 6 a, 6 b, 6 e, and 6 f. Furthermore, this second intra substrate connection terminal 4 d is also not connected to the semiconductor chip 3A. In FIG. 2, the second inter level connection terminal 4 c and the second intra substrate connection terminal 4 d are disposed adjacent to each other, however, it is not always necessary for both terminals to be disposed adjacent to each other. That is, the second inter level connection terminal 4 c or the second intra substrate connection terminal 4 d may be formed in the positions of other second lands, which are not shown in the cross section of FIG. 2.

As shown in FIG. 3, the outer periphery of the semiconductor chip 3A is covered with a chip passivating film 8. The chip passivating film 8 is provided to prevent damage to the semiconductor chip 3A at the time of conveying and packaging the first level assembly 100. This chip passivating film 8 is implemented by insulating materials such as resin.

As shown in FIG. 4, a window 41 is provided in the center of the mounting base 1A. In the window 41, the semiconductor chip 3A is exposed, which is disposed on the second surface of the mounting base 1A. A plurality of pads 43 a, 43 b, 43 c, . . . , 43 f, . . . are provided in the semiconductor chip 3A, and those pads are respectively connected to the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . by chip connection wiring 40 a, 40 b, 40 c, . . . , 40 f. An example shown in FIG. 4 is the first level assembly 100 called a center pad, however, other pad disposition can be employed as long as the pads 43 a, 43 b, 43 c, . . . , 43 f, . . . provided in the semiconductor chip 3A are respectively connectable to the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . . Note that, as apparent from FIG. 4, the first intra substrate connection terminal 7 d is insulated from the semiconductor chip 3A and the other connection terminals.

As shown in FIG. 5, second wiring layers 42 a and 42 s are embedded in the mounting base 1A. That is, the mounting base 1A has three metal wiring layers. Specifically, the metal wiring layers include: a first wiring layer 45 provided in the first surface; a third wiring layer 46 provided in the second surface; and the second wiring layers 42 a and 42 s embedded between the first surface and the second surface. For example, the power supply joint ball 5 a is connected to the through-hole 6 a from the first power supply terminal 7 a, and further connected to the embedded pad 43 a through the second chip connection wiring 42 a in the second wiring layer provided in the mounting base 1A. Similar to the power supply joint ball 5 a, the joint ball 5 s is connected to the embedded pad 43 s through the second chip connection wiring 42 s in the through-hole 6 s from a first land 7 s.

The mounting base 1A shown in FIGS. 1 to 5 employs a fan-out type substrate. That is, the size of the mounting base 1A is larger than that of the chip mounting area 2A. A thin tape such as a BGA tape is used as the mounting base 1A. As to the semiconductor chip 3A, for example, silicon having a thickness of about 0.28 to 0.45 mm can be employed. As to the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . and the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . , conductive thin films such as aluminum and copper are usable. As the joint balls 5 a, 5 b, 5 c, . . . , 5 f, solder balls are usable. The second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . , and the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . can be provided respectively on each of the first surface and the second surface with number of about 40 to 60 balls. For example, in the case of 256 MB SRAM, the following are provided: 13 address input pins; two bank select pins; 16 data input and output pins; a chip select pin, a row address pin, a column address pin, a write enable pin, an output disable pin, a write mask pin, a clock input pin, and a clock enable pin; three power supply pins (Vcc) and three power supply pins (GND), four power supply pins (VccQ) and 4 power supply pins (VssQ); and a non-connected pin. The number of the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . and the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . can be changed appropriately. The second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . may be embedded in the second surface of the mounting base 1A. The first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . may be embedded in the first surface of the mounting base 1A.

As described above, according to the first level assembly 100 of the first embodiment of the present invention, the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . and the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . are respectively disposed on the first surface and the second surface of the mounting base 1A. Accordingly, plural thin-type mounting bases 1A such as BGA tape can be stacked into a multi chip module (MCM). Moreover, for the first level assemblies 100 shown in FIGS. 1 to 5, all lands on the same surface have the same size. Therefore, when the first level assembly 100 is mounted on the packaging substrate, or when plural first level assemblies 100 are stacked, for example, damage to the lands can be prevented, which is caused by applying high pressure to certain lands. A non-connection state of certain lands can be also prevented because lands are all the same size. Therefore, according to the first level assembly 100 shown in FIGS. 1 to 5, the mounting substrate capable of high-density packaging, and the first level assembly 100 using the mounting substrate can be provided.

(Modification 1-1)

In the first level assembly 101 according to a first modification of the first embodiment of the present invention, as shown in FIG. 6, the plurality of second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . are provided in the form of a matrix over the remaining area of the second surface of the mounting base 1A where the chip mounting area 2A is disposed on. The joint balls 5 a, 5 b, 5 c, . . . , 5 i, . . . are embedded on the first surface side of the mounting base 1A so as to correspond accordingly to the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . of the second surface side through the first lands, which are not shown in FIG. 6. The constitution of other components is similar to that in the first level assembly 100 shown in the first embodiment. Since the first level assembly 101 shown in FIG. 6 also includes the first lands and the second lands on the first surface and the second surface of the thin-type mounting base 1A, respectively, the thin-type first level assemblies 101 is implemented by BGA tape, can be mounted in high density being stacked in multiple levels.

(Modification 1-2)

In the first level assembly 102 according to a second modification of the first embodiment of the present invention, as shown in FIG. 7, the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . are aligned along two lines on one side of a square, which defines the periphery of the mounting base 1A. The opposing side is a blank space. The joint balls 5 a, 5 b, . . . are connected to the first lands which are omitted in the drawing, disposed on the first surface of the mounting base 1A. Corresponding accordingly, the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . are disposed in a position opposite to the first lands connected to the joint balls 5 a, 5 b, . . . . The first lands of which are not shown in FIG. 7 are connected to the joint balls 5 a, 5 b, . . . . In the first level assembly 102 shown in FIG. 7, the thin-type first level assemblies can be mounted in high density by being stacked in multiple levels, such as the first level assembly 100 of the first embodiment.

(Modification 1-3)

In the first level assembly 103 according to a third modification of the first embodiment of the present invention, as shown in FIG. 8, a heat sink 11 is disposed so as to surround the circumference of the semiconductor chip 3A mounted on the second surface of the mounting base 1A. The heat sink 11 is used a metal such as aluminum. The first level assembly 103 shown in FIG. 8 can diseminate heat efficiently, which is generated from the semiconductor chip 3A, efficiently. Accordingly, when the plurality of first level assemblies are stacked in multiple levels, damage to the first level assembly 103 can be prevented by diseminating the heat efficiently, which is generated from semiconductor chips, efficiently.

(Second Embodiment)

As shown in FIGS. 9 and 10, in the first level assembly 200 according to a second embodiment of the present invention, a third surface of a upper level assembly 31 is disposed so as to face to a second surface of a first level assembly 30. That is, the first level assembly 200 as shown in FIGS. 9 and 10 further includes: a upper level mounting base 1B defined by the third surface and a fourth surface opposite to the third surface; upper level first lands 17 a, 17 b, 17 c, . . . , 17 f, . . . disposed on the third surface; and upper level second lands 14 a, 14 b, 14 c, . . . , 14 f, . . . disposed so as to face to the upper level first lands 17 a, 17 b, 17 c, . . . , 17 f, . . . respectively on the fourth surface. Second through-holes 16 a, 16 b, 16 e, . . . , 16 f . . . are embedded in the upper level mounting base 1B, so that some of the upper level first lands 17 a, 17 b, 17 c, . . . , 17 f, . . . are connected to some of the upper level second lands 14 a, 14 b, 14 e, . . . , 14 f, . . . which are just above the some of first lands 17 a, 17 b, 17 c, . . . , 17 f, . . . , respectively. Joint balls 15 a, 15 b, 15 c, . . . , 15 f, . . . are disposed in the upper level first lands 17 a, 17 b, 17 c, . . . , 17 f . . . respectively of the first level assembly 31. The upper level second lands 14 a, 14 b, 14 c, . . . , 14 f, . . . and the upper level first lands 17 a, 17 b, 17 c, . . . , 17 f, . . . are aligned along two sets of two lines are disposed, on opposing the sides of a square that defined the periphery on the second mounting base 2A. In the center of the fourth surface of the upper level assembly 31, an upper level chip mounting area 2B is assigned adjacent to the upper level second lands 14 a, 14 b, 14 c, . . . , 14 f, . . . . A upper level semiconductor chip 3B as an upper level chip is fixed to the second chip mounting area 2B with an adhesive or the like. Note that, since a fan-out type substrate is used in FIG. 9, the upper level second lands 14 a, 14 b, 14 c, . . . , 14 f, . . . of the upper level assembly 31 are not disposed in the positions just above the first semiconductor chip 3A of the first level assembly 30.

As shown in FIG. 10, a power supply terminal 17 a, a ground terminal 17 b, a input and output terminal 17 e, and an address terminal 17 f of the upper level assembly 31(the first group of the upper level first lands) are respectively connected to the upper level second lands 14 a, 14 b, 14 e, and 14 f (the first group of the upper level second lands) on the fourth surface of the upper mounting base 1B, by the second through-holes 16 a, 16 b, 16 e, and 16 f, which are embedded in the upper level mounting base 1B.

A first inter level connection terminal 17 c is electrically connected to the upper level semiconductor chip 3B by wiring, provided in the upper level mounting base 1B. The first intra substrate connection terminal 17 d (the second group of the upper level first lands) is connected to an inter level connection terminal 14 c (the second group of the upper level first lands) on the fourth surface of the second mounting base 1B by a second bent through-hole 19 (bent connection path), which has a stair-step shape and is provided in the second mounting base 1B. The second inter level connection terminal 14 c is not connected to the upper level semiconductor chip 3B, nor to the other upper level second lands 14 a, 14 b, 14 c, . . . , 14 f, . . . .

The first inter level connection terminal 17 c of the upper level assembly 31 works as a selection signal input terminal of the upper level semiconductor chip 3B. That is, the first inter level connection terminal 17 c connected to the upper level semiconductor chip 3B is connected to the second inter level connection terminal 4 c of the first level assembly 30 through the inter level joint ball 15 c, and is further connected to the first intra substrate connection terminal 7 d and the intra substrate joint ball 5 d by the bent through-hole 9. Accordingly, it is possible to operate the upper level semiconductor chip 3B of the upper level assembly 31 independent of the first level assembly 30 by feeding the selection signal from the intra substrate joint ball 5 d of the first level assembly 30. A description of the other components is omitted because those components have the same constitution as that of the components in FIGS. 1 to 5.

As described above, according to the first level assembly 200 of the second embodiment of the present invention, The thinner assembly can be made since the plate-shaped first level assembly 30 and the upper level assembly 31 are implemented by the BGA tape or the like, are stacked in two levels. In addition, assuming that each of the first level assembly 30 and the upper level assembly 31 are semiconductor recording devices, the recording capacitance of two first level assemblies can be obtained in an area required for one first assembly, by stacking the first level assembly 30 and the upper level assembly 31 longitudinally, whereby the recording capacitance can be increased. For example, as the first level assembly 30 and the upper level assembly 31 shown in FIG. 9, a DRAM, a flash memory, a SRAM, a mixed memory logic and the like are applicable. In addition, as shown in FIG. 10, since the first inter level connection terminal 7 c connected to the first semiconductor chip 3A of the first level assembly 30, and the first inter level connection terminal 17 c connected to the upper level semiconductor chip 3B of the upper level assembly 31 function as chip selection terminals independent of the other terminals, it is possible to operate the first level assembly 30 and the upper level assembly 31 independently. As described in the first embodiment, all of the second lands 4 a, 4 b, 4 c, . . . , 4 f . . . and the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . of the first level assembly 30, and the upper level second lands 14 a, 14 b, 14 c, . . . , 14 f., and the upper level first lands 17 a, 17 b, 17 c, . . . , 17 f . . . of the upper level assembly 31 have the same topology and the same shape. Accordingly, when the first level assembly 30 and the upper level assembly 31 are mounted in a stacked manner, the upper level assembly 31 can adhere to the first level assembly 30 without being conscious of the third surface and the fourth surface of the second mounting base 1B. Therefore, it is possible to achieve an improvement in the packaging operation efficiency.

Note that, as shown in FIG. 10, when the first level assemblies 100 to 103 shown in FIGS. 1 to 5 are stacked in two levels, at least one or more of the second intra substrate connection terminal 4 d and the first intra substrate connection terminal 17 d are included in the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . of the first level assembly 30 and the upper level first lands 17 a, 17 b, 17 c, . . . , 17 f, . . . of the upper level assembly 31. When the first level assemblies 100 to 103 are stacked in three levels, as shown in FIG. 11, at least two or more of the first lands for upper and lower connection, and the second lands for upper and lower connection are included in the same position of the respective upper level assembly 32 disposed in the uppermost level, the upper level assembly 31 disposed in the middle level, and the first level assembly 30 disposed in the lowermost level. When the first level assemblies are stacked in n levels (n is a natural number that is 2 or more), (n−1) of the first intra substrate connection terminals, and (n−1) of the second intra substrate connection terminals are included, respectively.

When the first level assembly 30 and the upper level assembly 31 are stacked as the first level assembly 200 shown in FIG. 9, the sum of the thickness of the second lands 4 a, 4 b, 4 c, . . . , 4 f., and the thickness of the upper level first lands 17 a, 17 b, 17 c, . . . , 17 f, . . . are formed being equal to or larger than that of the first semiconductor chip 3A for avoiding the compression of the first semiconductor chip 3A in the lower level. For example, in the semiconductor module shown in FIG. 10, assuming that the thickness of each of the first semiconductor chip 3A and the upper level semiconductor chip 3B is about 0.3 mm, the thickness of the second lands 4 a, 4 b, 4 c, . . . , 4 f, . . . , the upper level second lands 14 a, 14 b, 14 c, . . . , 14 f, . . . , the first lands 7 a, 7 b, 7 c, . . . , 7 f, . . . and the upper level first lands 17 a, 17 b, 17 c, . . . , . . . are set to about 0.3 mm. The semiconductor chip 3A and the upper level semiconductor chip 3B each having a thickness of 0.28 to 0.48 mm, and the BGA tape having the thickness of about 190 mm is usable, the BGA tape being used as the first mounting base 1A, and the second mounting base 1B. The BGA tape to be employed is one with an adhesive part of 50 mm, an insulation film of 75 mm, copper wiring of 15 mm, nickel wiring of 2 mm, gold wiring of 0.2 mm and an insulation film of 30 mm.

(Modification 2-1)

A structure will be described in which the first level assemblies 100 are stacked in three levels. As shown in FIGS. 11 and 12, the third surface of the upper level assembly 31 including the second mounting base 1B is disposed so as to face to the second surface of the first level assembly 30. Furthermore, a fifth surface of the upper level assembly 32 including a upper level mounting base 1C as the upper level mounting base is disposed so as to face to the fourth surface of the upper level assembly 31.

As shown in FIG. 12, the first first lands 7 a, 7 b, 7 f, and 7 g of the first level assembly 30 are respectively connected to the joint balls 15 a, 15 b, 15 f, and 15 g which are connected to the second lands 4 a, 4 b, 4 f, and 4 g through the first through-holes 6 a, 6 b, 6 f, and 6 g. The upper level first lands 17 a, 17 b, 17 f, and 17 g of the upper level assembly 31 connected to the joint balls 15 a, 15 b, 15 f, and 15 g are respectively connected to the upper level second lands 14 a, 14 b, 14 f, and 14 through the second through-holes 16 a, 16 b, 16 f, and 16 g (straight connection paths). Joint balls 25 a, 25 b, 25 f, and 25 g of the upper level assembly 32 are respectively connected to the upper level second lands 14 a, 14 b, 14 f, and 14 g. Third first lands 27 a, 27 b, 27 f, and 27 g, which are connected to the joint balls 25 a, 25 b 25 f and 25 g are connected to third second lands 24 a, 24 b, 24 f, and 24 g through third through-holes 26 a, 26 b, 26 f, and 26 g, (straight connection paths) respectively. The first first inter level connection terminal 7 c is electrically connected to the first semiconductor chip 3A by wiring, which is provided in the first mounting base 1A and is not shown in the drawing. The first intra substrate connection terminal 7 d is connected to the first second inter level connection terminal 4 c of the second surface through the first bent through-hole 9 provided in the first mounting base 1A. The second lower surface connection dedicated terminal 17 c, which is connected to the first second inter level connection terminal 4 c through the joint ball 15 c, is electrically connected to the upper level semiconductor chip 3B by wiring which is provided in the second mounting base 1B and is not shown in the drawing. The first intra substrate connection terminal 7 e is connected to the first upper surface connection dedicated terminal 4 d by the first bent through-hole 9 b provided in the first mounting base 1A. The second first intra substrate connection terminal 17 d, which is connected to the first upper surface connection dedicated terminal 4 d through the joint ball 15 d, is connected to the second upper surface connection dedicated terminal 14 c by a second bent through-hole 19 a (bent connection path) provided in the second mounting base 1B. The third first inter level connection terminal 27 c, which is connected to the second upper surface connection dedicated terminal 14 c through the joint ball 25 c, is electrically connected to the third semiconductor chip 3C by wiring, which is provided in the upper level mounting base 1C and is not shown in the drawing. The first intra substrate connection terminal 17 e is connected to the second intra substrate connection terminal 14 d by the bent through-hole 19 b (bent connection path) provided in the upper level mounting base 1B. A first intra substrate connection terminal 27 d, which is connected to the second intra substrate connection terminal 14 d through the joint ball 25 d, is connected to a second inter level connection terminal 24 c by a third bent through-hole 29 a (bent connection path) provided in the upper level mounting base 1C. A third first intra substrate connection terminal 27 e, which is connected to the second intra substrate connection terminal 14 e through the joint ball 25 e, is connected to a second inter level connection terminal 24 c by a bent through-hole 29 b (bent connection path) embedded in the upper level mounting base 1C. The first second intra substrate connection terminal 4 e, the second intra substrate connection terminal 14 e, and the second intra substrate connection terminal 24 e are not connected to the semiconductor chip 3A, the upper level semiconductor chip 3B, and the upper level semiconductor chip 3C. Note that, the upper level second lands 14 a, 14 b, 14 c, . . . , 14 g, . . . , the joint balls 25 a, 25 b, 25 c, . . . , 25 g, . . . , and the upper level first lands 27 a, 27 b, 27 c, . . . , 27 g, . . . adhere to each other by a thermo-compression bonding or the like, such as the first level assembly 200 shown in FIGS. 9 and 10.

According to the first level assembly 300 shown in FIG. 11, since the first level assembly 30, the upper level assembly 31, and the upper level assembly 32, which is implemented by the BGA tape and the like, are stacked in three levels, the volume of the assembly can be made smaller. In addition, the first inter level connection terminal 7 c, and the first intra substrate connection terminal 7 d and 7 e function as the chip selection terminals of the first level assembly 30, the upper level assembly 31, and the upper level assembly 32, whereby it is possible to operate the first level assembly 30, the upper level assembly 31, and the upper level assembly 32 independently.

(Third Embodiment)

A second level assembly 400 according to a third embodiment of the present invention includes, as shown in FIGS. 13 and 14: a packaging substrate 50 defined by a first surface having a first substrate mounting area 51A; first connection terminals 51 a, 51 b, 51 c, . . . , 51 x, . . . , which are aligned and disposed having intervals therebetween in the first substrate mounting area 51A of the first surface; signal terminals 53 a, 53 b, 53 c, . . . , 53 x, . . . which are disposed in the vicinity of the first substrate mounting area 51A; first signal wiring 52 a, 52 b, 52 c, . . . , 52 x, . . . which are connected to the first connection terminals 51 a, 51 b, 51 c, . . . , 51 x, . . . and the signal terminals 53 a, 53 b, 53 c, . . . , 53 x, . . . ; and a first level assembly 56 which is disposed in the first substrate mounting area 51A.

The packaging substrate 50 further includes a second substrate mounting area 51B on the first surface thereof. In a second substrate mounting area 51B, second connection terminals 511 a, 511 b, 511 c, 511 x, . . . are disposed having intervals therebetween. The second connection terminals 511 a, 511 b, 511 c, . . . , 51 x, . . . are connected to the signal terminals 53 a, 53 b, 53 c, . . . , 53 x, . . . by second signal wiring 522 a, 522 b, 522 c, . . . , 522 x, . . . . A first level assembly 57 is disposed in the second substrate mounting area 51B.

On the first level assemblies 56 and 57, for example, the first level assemblies 100 to 103, 200, and 300 shown in FIGS. 1 to 12 can be mounted. In FIG. 14, in the first substrate mounting area 51A, the first level assembly 56 having the same constitution as that of the first level assembly 200 is disposed. In the second substrate mounting area 51B, the first level assembly 57 having the same constitution as that of the first level assembly 100 shown in FIG. 1 is disposed. The first level assembly 57 includes: the first mounting base 30 as a second mounting base; first lands which are disposed on the first surface of the first mounting base 30, not shown in FIG. 14; and the second lands 4 a, 4 b, 4 c, . . . , 4 x, . . . which are disposed on the second surface so as to face to the first lands. In the second surface, which is adjacent to the second lands 4 a, 4 b, 4 c, . . . , 4 x, . . . , the semiconductor chip 3A as the second semiconductor chip is disposed. As shown in FIG. 14, packaging substrate joint balls 5 a, 5 b, 5 c, . . . , 5 x . . . of the first level assembly 56 are disposed on the first connection terminals 51 a, 51 b, 51 c, 51 x, . . . , which are disposed in the substrate mounting substrate 51A. The first lands of the mounting base 30 of the first level assembly 56, which is not shown in FIG. 14, are connected so as to be in contact with the packaging substrate joint balls 5 a, 5 b, 5 c, . . . , 5 x, . . . respectively. The joint balls 15 a, 15 b, 15 c, . . . , 15 x, . . . are respectively disposed in the second lands on the second surface of the mounting base 30, which are not shown in the drawing. Then, the first lands are disposed so as to be in contact with the joint balls 15 a, 15 b, 15 c, . . . , 15 x, . . . in the second mounting base 31 as in the upper surface mounting base, which is not shown in FIG. 14.

On the second connection terminals 511 a, 511 b, 511 c, . . . , 511 x, . . . disposed in the second substrate mounting area 51B as the second substrate mounting area, the packaging substrate joint balls 5 a, 5 b, 5 c, . . . , 5 x, . . . of the first level assembly 57 are disposed. The first lands of the mounting base 30 of the first level assembly 57, which are not shown in FIG. 14 are connected so as to be in contact with the assembling substrate joint balls 5 a, 5 b, 5 c, . . . , 5 x, . . . , respectively.

In the first connection terminals 51 a, 51 b, 51 c, . . . , 51 x, . . . disposed in the first substrate mounting area 51A, for example, included are: an ADD terminal 51 a for supplying the address signal; an input and output terminal 51 b for supplying the input and output signal; chip selection terminals 51 c and 51 d for selecting the semiconductor chips; a GND terminal 51 e; and a VDD terminal 51 f and the like. The ADD terminal 51 a, the input and output terminal 51 b, the chip selection terminals 51 c and 51 d, the GND terminal 51 e, and the VDD terminal 51 f receive signals from the ADD signal terminal 53 a, an input and output terminal 53 b, chip selection signal terminals 53 c and 53 d, a GND signal terminal 53 e, and a VDD signal terminal 53 f. The second connection terminals 511 a, 511 b, 511 c, . . . , 511 x, . . . in the second substrate mounting area 51B include: the ADD terminal 511 a for supplying the address signal; the input and output terminal 511 b for supplying the input and output signal; the chip selection terminals 511 c and 511 d for selecting the semiconductor chip; the GND terminal 511 e;

-   -   the VDD terminal 511 f, and the like. The ADD signal 511 a, the         input and output terminal 511 b, the chip selection terminals         511 c and 511 d, the GND terminal 511 e and the VDD terminal 511         f receive signals from the ADD signal terminal 53 a connected to         the first signal wiring 52 a, 52 b, 52 c, . . . , 52 f, the         input and output signal terminal 53 b, the chip selection signal         terminals 53 c and 53 d, the GND signal terminal 53 e and the         VDD signal terminal 53 f. The signal terminals 53 a, 53 b, 53 c,         . . . , 53 x, . . . include a write signal terminal, a clock         input signal terminal and the like, other than the ADD signal         terminal 53 a, the input and output terminal 53 b, the chip         selection signal terminals 53 c and 53 d, the GND signal         terminal 53 e and the VDD signal terminal 53 f.

According to the second level assembly 400 of the third embodiment of the present invention, the thin-type first level assembly 57 using the BGA tape and the like, and the first level assembly 56 in which the first level assemblies 57 are stacked in multiple levels can be mounted onto one piece of the packaging substrate 50. The operation of the first level assembly 30 and the upper level assembly 31 of the first level assembly 56 can be performed independently by the chip selection signal terminals 53 c and 53 d, which are insulated from the other terminals.

Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing form the scope thereof. 

1-20. (canceled)
 21. A semiconductor device, comprising: a first mounting base defined by a first surface and second surface opposite to the first surface, the first surface having a first mounting area and a plurality of first lands, the second surface having a plurality of second lands opposite to the first lands, and each of the first lands are electrically connected to one of the second lands via a first through-hole, respectively; a first semiconductor chip mounted on the first mounting area having a plurality of first pads electrically connected to the second lands, respectively; a second mounting base mounted on the first mounting base having a same size as the first mounting base defined by a third surface and fourth surface opposite to the third surface, the third surface having a second mounting area and a plurality of third lands, the fourth surface having a plurality of fourth lands opposite to the third lands, each of third lands is electrically connected to one of the fourth lands via a second through-hole, respectively, each of fourth lands is electrically connected to one of the first lands via a first joint ball, respectively, and a second semiconductor chip mounted on the second mounting area having a plurality of second pads electrically connected to the first lands via the fourth lands, respectively.
 22. The semiconductor device of claim 21, wherein a distance between the first surface and the fourth surface is longer than the distance between the first surface and an upper surface of the first semiconductor chip.
 23. The semiconductor device of claim 21, wherein the first and the second mounting base are BGA tapes.
 24. The semiconductor device of claim 21, wherein the first semiconductor chip is mounted in a face down configuration on the first chip mounting area.
 25. The semiconductor device of claim 21, further comprising: a first heat sink contacted to the first semiconductor chip.
 26. The semiconductor device of claim 21, wherein the first lands are provided in the form of matrix over the remaining area of the first mounting area on the first surface.
 27. The semiconductor device of claim 21, wherein the first lands are aligned along a plurality of lines on one side of a square defining a periphery of the first mounting base.
 28. The semiconductor device of claim 21, wherein the first joint ball is made from solder.
 29. The semiconductor device of claim 21, further comprising: a third mounting base mounted on the second mounting base having same size as the first mounting base defined by a fifth surface and sixth surface opposite to the fifth surface, the fifth surface having a third mounting area and a plurality of fifth lands, the sixth surface having a plurality of sixth lands opposite to the fifth lands, each of the fifth lands is electrically connected to one of the sixth lands via a third through-hole, respectively, each of sixth lands is electrically connected to the first lands via a second joint ball, respectively; and a third semiconductor chip mounted on the third mounting area.
 30. The semiconductor device of claim 21, further comprising: a packaging board having a plurality of terminals; and a plurality of packaging balls disposed on the terminals, wherein the terminals are connected to the second lands via the packaging balls.
 31. The semiconductor device of claim 21, further comprising: a packaging board having a substrate mounting area; a plurality of connection terminals disposed on the substrate mounting area; a plurality of signal terminals disposed around the substrate mounting area on the packaging board; a plurality of signal wiring connected to the connection terminals and the signal terminals; a plurality of packaging balls disposed on the connection terminals, respectively, wherein the second lands are connected to the connection terminals via the packaging balls. 